Quaternary ammonium salts as a conversion coating or coating enhancement

ABSTRACT

Disclosed are quaternary ammonium salts containing non-halogen anions such as carbonates, bicarbonates, phosphates, glycolates and mixtures thereof as conversion coatings or additives imparting anti-corrosive properties to paints. The invention relates to a method for inhibiting the corrosion of metal surfaces by applying a composition containing one or more quaternary ammonium carbonate or bicarbonate. The disclosure is also directed to anti-corrosive coatings for metal substrates containing these compounds and to metal substrates having these anticorrosive coatings.

CROSS REFERENCE TO RELATED APPLICATION

This application claims the benefit of U.S. Provisional Application No.60/634,793, filed Dec. 9, 2004, which is hereby incorporated byreference.

FIELD OF THE INVENTION

The present invention relates to the use of quaternary ammonium saltscontaining non-halogen anions such as carbonate, bicarbonate, phosphateand glycolate as active ingredients of conversion coatings and asadditives for paints and coatings.

BACKGROUND OF THE INVENTION

In processes where metal surfaces come in contact with water, whether asliquid water or humid air, there is always the danger of corrosion. Thisis particularly problematic when the metal itself is prone to corrosionand is not coated.

Examples of metals prone to corrosion are found in stamped metal carparts made from ferrous alloys, abraded surfaces such as machined steelparts, and machine components made from cast iron.

Conversion coatings are used to inhibit corrosion and to assure goodadhesion of paint to a metal surface, in particular to steel. Bare steeldoes not form a good bond with organic coatings. To improve themetal/organic coating bond, chromate or phosphate conversion coatingsare chemically reacted with the steel to form a rough surface structurewith metal-phosphate platelets that provide both mechanical and chemicalkeying (adhesion) of the organic polymer to the metal surface. See, forexample, Watson, J. “A refresher: Understanding pretreatment”, PowderCoating 1996, 7(3) and Ferguson, D.; Monzyk, B., “Nonpollutingreplacement for chromate conversion coating and zinc phosphate in powdercoating applications”, Powder Coating 2001, 12(7). Here and hereinbelow,a conversion coating is to be understood to mean a protective barrierfilm or layer on the metal substrate surface simultaneously capable ofboth corrosion inhibition and paint adhesion and comprised of either (i)an organic film, (ii) an inorganic oxide resulting from a metal etchingand redeposition process, (iii) an inorganic oxide resulting from a truedeposition process, or (iv) any mixture of inorganic and organicmaterials from (i), (ii) and (iii). The most widely used conversioncoatings are chromating, phosphochromating and zinc phosphatizingprocesses. It is believed that chromating gives better corrosioninhibition, while phosphochromating gives better paint adhesion. Priorto applying the conversion coating to the metal surface, the metalsurface must be cleaned in order to remove any grease on the metalsurface. The conversion coating can then be applied by either immersionor spraying. Chromate and phosphochromate conversion coatings are themost common chemical conversion coatings, but because of health, safetyand environmental concerns other types of conversion coatings areneeded.

SUMMARY OF THE INVENTION

It has been discovered that quaternary ammonium salts containingnon-halogen anions such bicarbonate, carbonate, phosphate and glycolate,more specifically, dialkyl dimethyl ammonium salts containingbicarbonate, carbonate, phosphate or glycolate as the anion, and variouscombinations thereof, have applicability as a conversion coating formetal surfaces and steel in particular. Additionally it has beendiscovered that said quaternaries are capable of effecting a desirablesurface transformation such as the growth of desirable surface oxides(i.e. magnetite, Fe₃O₄) on steel substrates. This oxide formationresults in distinct crystallite domains which adhere to the metalsubstrate and to which coatings such as paints are expected to exhibitimproved adhesion. In addition, said quaternary ammonium salts can beadded directly to paints to provide better adhesion of the paint to themetal surface and thereby improving corrosion resistance.

The corrosion inhibition properties of quaternary ammonium carbonatesand bicarbonates have been disclosed in copending U.S. patentapplication Ser. No. 10/810,279 (US 2005/0003978 A1). Additionally ithas now been discovered that under the inhibitor film, a protected steelsurface grows desirable surface oxides (i.e., magnetite, Fe₃O₄). Thisoxide formation creates domains to which organic coatings such as paintsare expected to exhibit improved adhesion.

DETAILED DESCRIPTION OF THE INVENTION

Surprisingly, it has been found that certain quaternary ammonium saltscontaining non-halogen anions, such as di-n-decyldimethylammoniumcarbonate, when applied to the surface of iron and iron alloys such assteel, have a propensity to effect a known, desirable transformation onthe surface of iron and iron alloys such as steel under much milderconditions of temperature than previously known. While thermally inducedtransformations of steel surfaces at >110° C. are known in the art, thehigh temperatures required to effect those transformations haveheretofore limited their commercial exploitation. However the abovementioned quarternary ammonium salts appear capable of effecting asimilar transformation of steel surfaces at temperatures as low as roomtemperature.

Additionally, the unique nature of the above quaternary ammonium salts(either neat or in formulation) allows for a one step metal surfacepreparation process prior to final coating applications. It has beenfound that metal exposure to their solutions will simultaneously clean,corrosion inhibit, and primer coat metal surfaces in preparation forfinal coating applications. This represents a significant improvementover current processes which perform the following independent functionsin a stepwise fashion and with significantly greater amounts ofindustrial effluents which must be disposed of:

a) the raw metal is passivated with oil to prevent flash rust.b) the passivation oil is removed and disposed ofc) the metal surface is treated with conversion coating solutions(acidic, heavy metal containing chemicals) and cured before the finalcoating is applied.

It has also been found that steel surfaces treated according to thepresent invention are resistant to flash rusting. Flash rusting occurswhen a newly formed bare steel surface is exposed to water and reacts toform a red iron hydroxide rust layer.

Coiled sheet steel treated according to the present invention isresistant to the edge staining that occurs when moisture condenses onthe edges of the coils. Presently steel sheet is sprayed with a lightoil prior to storage or transportation. This oil must be removed priorto additional surface treatments or coatings.

The oxide film formed according to the present invention has thepotential of being an under-paint conversion coating or primer forsteel. Bare steel does not form a good bond with organic coatings. Toimprove the metal/organic coating bond, chromate or phosphate conversioncoatings are chemically reacted with the steel to form a rough surfacestructure with metal-phosphate platelets that provide both mechanicaland chemical keying (adhesion) of the organic polymer to the metalsurface.

It has also been found that the conversion coatings and anticorrosivepaints of the present invention exhibit certain self-healing propertieson scratching, which means that even the “bare” metal surface in ascratch shows some passivation that may be due to migration of thequaternary ammonium salt from the surrounding coating. In some cases, apermanent oxide transformation is also observed resulting in long termpassivation of a scratched area. This is an effect that is similar tothe self-healing observed on chromium coated metal surfaces.

In particular, the present invention relates to a method for applying aconversion coating to the surface of a metal substrate, said methodcomprising the step of contacting the substrate with a compositioncomprising

(a) at least one quaternary ammonium salt containing a non-halogen anionand(b) optionally, a solvent.

According to one preferred embodiment, the composition includes fromabout 0.05 to about 2% by weight and more preferably from about 0.1 toabout 1% by weight of the quaternary ammounium salt(s) containingnon-halogen anion(s), based upon 100% total weight of the composition.

Preferably, the quaternary ammonium salt has the formula

wherein R¹ is an optionally aryl-substituted C₁₋₂₀ alkyl group, and R²is an optionally aryl-substituted C₁₋₂₀ alkyl group, R³ and R⁴independently of each other are C₁₋₄ alkyl groups, X^(n−) is an anionselected from the group consisting of hydroxide, carbonate, bicarbonate,phosphates, phosphites, hypophosphite, nitrate, sulfates, borates,anions of saturated and unsaturated acyclic C₁₋₂₀ monocarboxylic acids,anions of saturated and unsaturated C₂₋₂₀ dicarboxylic acids, and anionsof hydroxy-substituted carboxylic acids, and n denotes the appropriatenumber of negative charges of said anion.

Here and hereinbelow, C₁₋₂₀ alkyl groups are linear or branched alkylgroups having 1 to 20 carbon atoms, including, but not limited to,methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl,tert-butyl, pentyl, isopentyl, hexyl, heptyl, octyl, nonyl, isononyl,decyl, dodecyl, tetradecyl, hexadecyl, octadecyl and icosyl.Aryl-substituted C₁₋₂₀ alkyl groups are any of the above groups bearingan aryl group, in particular phenyl, as a substituent. Preferredexamples of aryl-substituted C₁₋₂₀ alkyl groups are benzyl, phenylethyland phenylpropyl.

The term “phosphates” is to be understood as including both acid andneutral salts of phosphoric acid, namely, dihydrogenphosphates (H₂PO₄⁻), monohydrogenphosphates (HPO₄ ²⁻) and phosphates (PO₄ ³⁻), as well assalts of oligo- and polyphosphoric acids such as diphosphates(pyrophosphates) and triphosphates.

Phosphites are salts of phosphorous acids containing the anions H₂PO₃ ⁻and/or HPO₃ ²⁻.

Sulfates are hydrogensulfate (HSO₄ ⁻) and sulfate (SO₄ ²⁻) as well asdisulfate (S₂O₇ ²⁻) and related anions.

Borates are any anions derived from boric acid (H₃BO₃) and the variouspolyboric acids.

Saturated and unsaturated acyclic C₁₋₂₀ monocarboxylic acids are inparticular alkanoic acids, such as formic, acetic, propionic, butyric,pentanoic, hecanoic, octanoic, decanoic, dodecanoic, tetradecanoic,hexadecanoic, octadecanoic and icosanoic acids, or alkenoic acids, suchas acrylic, methacrylic, oleic and linolic acid.

Saturated and unsaturated acyclic C₂₋₂₀ dicarboxylic acids are inparticular alkanedioic acids, such as oxalic, malonic, succinic,glutaric and adipic acid, or alkenedioic acids such as fumaric or maleicacid.

Hydroxy-substituted carboxylic acids are any carboxylic acids bearing atleast one hydroxy group in addition to the carboxylate group(s), such asglycolic, malic, citric or salicylic acid.

More preferred quaternary ammonium salts exhibiting the effect describedabove are quaternary ammonium carbonates, quaternary ammoniumbicarbonates, quaternary ammonium phosphates and quaternary ammoniumglycolates.

Still more preferably, R³ and R⁴ in the quaternary ammonium salt offormula I are methyl groups.

In a preferred embodiment, R¹ is methyl.

In a more preferred embodiment, R² is benzyl or phenylethyl.

In another preferred embodiment, R¹ and R² are the same C₁₋₂₀ alkylgroups.

In a more preferred embodiment, R¹ and R² are C₁₀ alkyl groups.

In an even more preferred embodiment, R¹ and R² are n-C₁₀ alkyl groups.

In a particularly preferred embodiment, the quaternary ammonium salt isdi-n-decyldi-methylammonium carbonate and/or di-n-decyldimethylammoniumbicarbonate.

Preferably, the metal substrate is steel.

More preferably, the steel is coiled sheet steel.

Another object of the invention is an article of manufacture comprisinga metal substrate treated according to the above described method or anyof its preferred embodiments.

Again, the preferred metal substrate is steel.

Still another object of the invention is an anticorrosive paintcomprising

(a) at least one quaternary ammonium salt containing a non-halogenanion,(b) a binder,(c) optionally, a solvent and(d) optionally, a pigment.

According to one preferred embodiment, the anticorrosive paint includesfrom about 0.05 to about 2% by weight and more preferably from about 0.1to about 1% by weight of the quaternary ammounium salt(s) containingnon-halogen anions, based upon 100% total weight of the paint.

As in the method described above, the quaternary ammonium salt in theanticorrosive paint preferably has the formula

wherein R¹ is an optionally aryl-substituted C₁₋₂₀ alkyl group, and R²is an optionally aryl-substituted C₁₋₂₀ alkyl group, R³ and R⁴independently of each other are C₁₋₄ alkyl groups, X_(n−) is an anionselected from the group consisting of hydroxide, carbonate, bicarbonate,phosphates, nitrate, sulfates, borates, anions of saturated andunsaturated acyclic C₁₋₂₀ monocarboxylic acids, anions of saturated andunsaturated C₂₋₁₂ dicarboxylic acids, and anions of hydroxy-substitutedcarboxylic acids, and n denotes the appropriate number of negativecharges of said anion.

The further preferred embodiments of the quaternary ammonium salt in theabove described method apply analogously to the anticorrosive paint.

Preferably, the binder is selected from the group consisting of acrylicresins, casein (milk protein), vinyl resins, latex resins, acetateresins, epoxy resins and mixtures thereof.

In a preferred embodiment, the anticorrosive paint is a latex paint.

In another preferred embodiment, the anticorrosive paint is an enamelspray paint.

In a further preferred embodiment, the anticorrosive paint is anE-Coating paint.

In still another preferred embodiment, the anticorrosive paint is anacrylic paint.

Still another object of the invention is an article of manufacturecomprising a metal substrate painted with the above describedanticorrosive paint. All preferred embodiments regarding the nature ofthe anticorrosive paint, the ammonium salt being comprised in saidpaint, and the metal substrate apply likewise to said article ofmanufacture.

Still another object of the invention is the use of a quaternaryammonium salt having the formula

wherein R¹ is an optionally aryl-substituted C₁₋₂₀ alkyl group, and R²is an optionally aryl-substituted C₁₋₂₀ alkyl group, R³ and R⁴independently of each other are C₁₋₄ alkyl groups, X^(n−) is an anionselected from the group consisting of hydroxide, carbonate, bicarbonate,phosphates, phosphites, hypophosphite, nitrate, sulfates, borates,anions of saturated and unsaturated acyclic C₁₋₂₀ monocarboxylic acids,anions of saturated and unsaturated acyclic C₂₋₂₀ dicarboxylic acids andanions of hydroxy-substituted carboxylic acids, and n denotes theappropriate number of negative charges of said anion as an anticorrosiveadditive in paints or coatings.

The further preferred embodiments of the quaternary ammonium salt in theabove described method apply analogously to the use as an anticorrosiveadditive.

DESCRIPTION OF THE DRAWINGS

FIG. 1 is a SEM micrograph of a steel surface after two weeks immersionin 3.5% aqueous NaCl solution containing 0.1% di-n-decyldimethylammoniumcarbonate. Note the formation of hexagonal platelets on the surface.

FIG. 2 is a SEM micrograph of a steel surface after two months immersionin 3.5% aqueous NaCl solution containing 0.1% di-n-decyldimethylammoniumcarbonate. The surface is covered with platelets and sphericalparticles. One of these phases is ferromagnetic (magnetite, Fe₃O₄).

FIG. 3 is a SEM micrograph of a steel surface after 48 h immersion at70° C. in a 0.1% solution of di-n-decyldimethylammonium glycolate in tapwater.

FIG. 4 is a SEM micrograph of a steel surface after 1 h immersion at 70°C. in tap water (control experiment).

FIG. 5 depicts the results of paint peel back tests with severalE-coated steel samples after salt spray exposure.

FIG. 6 depicts the results of salt spray tests of steel samples paintedwith latex paint made anticorrosive by addition of quaternary ammoniumsalts.

FIG. 7 depicts the results of salt spray tests of steel samples paintedwith gloss protective spray enamel with various amounts of quaternaryammonium salts.

The following examples illustrate the invention, but are not limitingthereof. All parts and percentages are given by weight unless otherwisestated.

Example 1

A Conversion Coating Study (Reference: N135751-001 through 018) was donewith the objective to prepare steel panels (S-46, purchased from Q-PanelLab Products, Cleveland, Ohio) with various aqueous treatments of eitherCarboShield® 1000 (di-n-decyldimethyl-ammonium bicarbonate/carbonate),“Phosphoquat” (di-n-decyldimethylammonium phosphates), and variousrelated controls.

A plastic tank being 27.9 cm (11″) in diameter and 27.9 cm (11″) inheight was used to treat the panels. The plastic tank was filled with9,600 grams of test solution.

10.16 cm×15.24 cm×1.59 mm (4″×6″× 1/16″) steel (S-46) panels with a holeof 6.35 mm (¼″) in diameter located 6.35 mm (¼′) from the top edge weretreated by placing a plastic pipette through the hole in the panel. Upto three panels were skewed using the same pipette. This allowed for thepanels to stand upright, with only the bottom of the panel touching thebottom of the tank. The tank was then placed in an oven which was at 70°C. for one hour. After one hour, the panels were removed from the tank,dried with a paper towel and then wrapped in a plastic wrap and labeled.The test solutions prepared can be found in the list below. Allconcentrations are given in percents by weight. The concentrationsstated for CarboShield® and Phosphoquat are the true concentrations ofthe active compound(s):

Test Solutions Deionized Water Tap Water (Allendale, N.J.) 5% Salt(NaCl) Water

0.1% CarboShield® 1000*⁾ in Deionized Water *⁾ Carbo Shield® 1000 is a50% aqueous solution of di-n-decyldimethylammonium (bi)carbonate (90 mol% bicarbonate, 10 mol % carbonate).

0.1% CarboShield® 1000 in Tap Water (Allendale, N.J.) 0.1% CarboShield®1000 in 5% Salt (NaCl) Water

0.1% Phosphoquat**⁾ (pH=2.5) in Deionized Water **⁾ Phosphoquat is asolution of di-n-decyldimethylammonium (hydrogen)phosphate(s) preparedby adding the amount of 85% aqueous phosphoric acid required to obtainthe specified pH to CarboShield® 1000.0.1% Phosphoquat (pH=4.0) in Deionized Water0.1% Phosphoquat (pH=7.5) in Deionized Water0.1% Glycoquat***⁾ (pH=7.5) in Deionized Water **⁾ Glycoquat is asolution of di-n-decyldimethylammonium glycolate(s) prepared by addingthe amount of glycolic acid required to obtain the specified pH toCarboShield® 1000.

After the steel panels were treated with the test solutions, they werepainted using three different painting processes. Two panels werepainted for each painting process. In one of the painting processes, thesteel panels were spray painted using Rust-Oleum®'s Professional HighPerformance Enamel (Hunter Green) spray paint. Four steel panels werelaid flat end to end and spray painted with approximately 18 g of paintapplied to the top surface of the steel panels and allowed to dryovernight. The bottom of the panels were treated in a similar manner thenext day. A second set of panels were painted using Rust-Oleum®'sPainters Touch® (Hunter Green) latex paint. The paint was applied with afoam roller to the steel panels. A total of two coats of paint wereapplied to each side of the steel panels. A third set of panels werepainted using a commercial painting process known as E-Coating (apolymer based coating). These samples were painted at Royal E-Coat(Costa Mesa, Calif.), using a proprietary process. A fourth set of steelpanels (untreated) were also painted using Rust-Oleum®'s Painters Touch®(Hunter Green) latex paint to which CarboShield® 1000 was added ateither 0.1%, 0.5% or 1.0%. A fifth set of steel panels (untreated) werealso painted using Rust-Oleum®s Gloss Protective Spray Enamel (HunterGreen) paint to which CarboShield® 1000, phosphoquat, or glycoquat wasadded at indicated levels.

All of the painted samples were sent to Assured Testing Services (224River Rd., Ridgeway, Pa. 15853) for salt spray testing (ASTM B117). Oneset of panels were scored with an “X” in the center of the panel. Theamount of paint pull back for the scored X was measured (in mm) in 5different locations. The measurements were then averaged. The lower theaverage value, the better was the performance of the treatment. Thesamples were measured at different time intervals during the course ofthe testing. The second set was edge coated with wax to prevent edgeeffects. The undisturbed panel surface was periodically evaluated fortotal visible rust and rated from 0 to 100%.

Conversion Coating/Paint/Salt Spray Testing Results:

The panels that were spray painted (enamel) exhibited the largestimprovement in paint adhesion relative to the control samples. For mostof the test samples evaluated, the latex paint samples did not showdifferences between test sample and the corresponding controls. TheE-Coat samples exhibited the least amount of paint pull back after 144hours. The relevant results where differences exist between the testsample and the control are compiled in Tables 1 and 2 below.

TABLE 1 Rating*⁾ (after 144 hours) Type of Water Used Additive TreatmentPaint Type (Amount of Paint Pull Back) 5% Salt Water CarboShield ® 1000Enamel Spray Paint 7.36 5% Salt Water None Enamel Spray Paint 12.36(Control) None None Enamel Spray Paint 13.89 (Control) Deionized WaterPhosphoquat (pH = 7.5) Enamel Spray Paint 5.71 Deionized WaterCarboShield ® 1000 Enamel Spray Paint 7.63 Deionized Water PhosphoricAcid (pH = 4.0) Enamel Spray Paint 8.86 Deionized Water Phosphoquat (pH= 2.5) Enamel Spray Paint 9.87 Deionized Water Phosphoquat (pH = 4.0)Enamel Spray Paint 9.98 None None Enamel Spray Paint 13.89 (Control)Deionized Water None Enamel Spray Paint 15.20 (Control) Tap WaterCarboShield ® 1000 Enamel Spray Paint 10.04  Tap Water None Enamel SprayPaint 11.86 (Control) None None Enamel Spray Paint 13.89 (Control) TapWater CarboShield ® 1000 Latex Paint 7.65 Tap Water None Latex Paint 9.10 (Control) Tap Water None Latex Paint  9.12 (Control) DeionizedWater Phosphoquat (pH = 2.5) Latex Paint 5.95 Deionized Water None LatexPaint  6.87 (Control) *⁾Average paint peel in mm.

This data clearly demonstrates dramatic improvements to paint peel inthe case of a commercial spray enamel when the test panel is pre-treatedwith CarboShield® 1000 and phosphoquat materials.

TABLE 2 Summary of average paint peel back data for E-coated samples.Sample Salt Spray Hours ID Description 48 144 384 552 B10 Ecoat control,salt 0.97 3.31 6.22 7.32 A10 Ecoat, control, untreated 1.15 2.42 4.617.24 E32 Phosphoric Acid, control 0.79 2.49 5.57 6.22 B16 CS1000, Ecoat1.65 2.71 5.74 7.11 F8 Ecoat MP10 1.12 2.43 3.85 5.76 D16 Ecoat CS 10001.07 3.04 5.53 5.59 E14 PQ2.5 Ecoat 1.10 2.36 4.40 5.46 E16 PQ4.0 Ecoat1.53 3.07 4.15 4.93 E18 PQ7.5, Ecoat 1.12 2.00 2.76 3.09 PQ =Phosphoquat; CS = CarboShield ®; DI = deionized water.

The results listed in Table 2 are also depicted in FIG. 5.

A duplicate set of unscored paint panels was prepared and subjected tosalt spray exposure testing. Table 3 below is a summary table of the keyresults where differences exist between the test sample and the control.

TABLE 3 Summary of key undisturbed test panel surfaces salt spraytesting Water Used Additive Treatment Paint Type % Visual Rust Time (h)Deionized Water Phosphoquat (pH = 2.5) Latex 20% 288 Deionized WaterPhosphoquat (pH = 4.0) Latex 20% 288 Deionized Water Phosphoquat (pH =7.5) Latex 40% 288 Deionized Water Phosphoric acid (pH = 4.0) Latex 10%(Control) 288 Deionized Water None Latex 75% (Control) 288 5% Salt WaterCarboShield ® 1000 Enamel Spray 20% 288 5% Salt Water None Enamel Spray75% (Control) 288 Deionized Water Phosphoquat (pH = 2.5) Enamel Spray 10456 Deionized Water CS MP10 Enamel Spray 15 456 Deinonized WaterCarboShield ® 1000 Enamel Spray 15 456 Deionized Water Phosphoquat (pH =4.0) Enamel Spray 40 456 Deionized Water Phosphoric acid (pH = 4.0)Enamel Spray 40% (Control) 456 Deionized Water None Enamel Spray 40 456Deionized Water Phosphoquat (pH = 7.5) Enamel Spray 50 456 Tap WaterCarboShield ® 1000 Enamel Spray  5 624 Tap Water None Enamel Spray 15624

Collectively, this data demonstrates a dramatic ability of bothCarboShield® 1000 and the phosphoquat version “conversion coating”pretreatments to significantly reduce total rust of a commercial latexand a spray enamel treatment in salt spray testing.

TABLE 4 Peel back data for CarboShield ® 1000 added to brush latex“Spiking” Treatment Peel Rating (144 h) 1.0% CarboShield ® in LatexPaint 3.79 0.1% CarboShield ® in Latex Paint 5.97 0.5% CarboShield ® inLatex Paint 6.98 0.0% CarboShield ® in Latex Paint 9.12

This data shows dramatic improvements in paint peel when CarboShield®1000 is incorporated directly into a commercial paint formulation.

In another test, the amount of visual rust (in %) was determined forundisturbed test panel surfaces painted with latex paint spiked withvarious amounts of CarboShield® 1000 (CS) after salt spray exposure for24 to 456 h. The data is compiled in Table 5 below and depicted in FIG.6.

TABLE 5 Undisturbed test panel surfaces for latex paint spiked withCarboShield ® 1000. Sample G1 Sample A5 Time 0.1% CS Spike, Sample G3Sample G5 Brushed, (h) Brush 0.5% CS Spike 1% CS Spike Untreated 24 1 11 1 48 1 1 1 1 120 20 144 15 20 30 192 25 216 25 45 288 35 3 80 312 5 35336 10 360 45 85 456 75 15 40 95 Samples were prepared by brushapplication.

In another test, the amount of visual rust (in %) was determined forundisturbed test panel surfaces painted with gloss protective sprayenamel with various amounts of CarboShield® 1000 (CS), phosphoquat, andglycoquat after salt spray exposure for 24 to 168 h. The data iscompiled in Table 6 below and depicted in FIG. 7.

TABLE 6 Undisturbed test panel surfaces for gloss protective sprayenamel (GPE) spiked with CarboShield ® 1000 (CS), phosphoquat (PQ), andglycoquat (GQ). Time (h) Sample Description 24 48 72 96 168 GPE sprayenamel 0.5 15 45 80 87.5 (control) 0.25% GQ (spiked) 0 0 0 0 12.5 0.50%GQ (spiked) 0 0 0 0 2.5 0.25% CS (spiked) 0 0 0 0.5 12.5 0.50% CS(spiked) 0 0 0 0 1.5 0.25% PQ4.0 (spiked) 0 0 0.5 0 3 0.50% PQ4.0(spiked) 12.5 12.5 0 35 77.5 All samples were prepared by brushapplication in order to allow for spiking where applicable.

The data in tables 5 & 6 shows dramatic improvements in corrosionresistance when CarboShield® 1000 or related phosphoquat or glycoquatmaterials are incorporated directly into commercial paint formulations.

Example 2 & Comparative Example 1

Two latex paints were formulated according to the amounts and order ofingredients and process steps listed in Table 7. One formulation(Example 2) contained CarboShield® 1000 while the other one (ComparativeExample 1) contained a combination of a nonionic surfactant (TritonX-100) and a conventional corrosion inhibitor (Canguard® 327).

TABLE 7 Summary of Formulated Ingredients Comp. Material/Process StepExample 1 Example 2 Water 57.34 L 57.34 L Propylene glycol 15.42 kg15.42 kg Natrosol ® 250 HBR 816.5 g 816.5 g Mix 30 minutes Tamol ® 8504.536 kg 4.536 kg Triton ® X-100 1.043 kg — CarboShield ® 1000 — 1.043kg Drewplus ® L-493 861.8 g 861.8 g Canguard ® 327 1.021 kg — AMP-95 ™453.6 g 453.6 g Mix Ti-Pure ® R-931 87.32 kg 87.32 kg Imsil ® A-15 87.32kg 87.32 kg High speed stir at 4,000 RPM for 30 min, then decrease speedto 1,000 RPM UCAR ® 123 latex 154.0 kg 154.0 kg Texanol ® 3.080 kg 3.080kg Drewplus ® L-493 997.9 g 997.9 g Acrosol ® RM-825 907.2 g 907.2 gWater 81.29 L 81.29 L Allow to sit for 48 hours to test for stabilityand dispersion before testing material Natrosol ® 250 HBR is a watersoluble hydroxyethylcellulose of Hercules Inc., Wilmington, Delaware.Tamol ® 850 is a sodium polyacrylate of Rohm and Haas Co., Philadelphia,Pennsylvania. Triton ® X-100 is an octylphenol ethoxylate of The DowChemical Company. Drewplus ® L-493 is a defoamer of Ashland SpecialtyChemical Co., Boonton, New Jersey. Canguard ® 327 is anoxazolidine-based corrosion inhibitor of ANGUS Chemical Company, asubsidiary of The Dow Chemical Company. AMP-95 ™ is2-amino-2-methyl-1-propanol containing 5% water, obtainable from ANGUSChemical Company. Ti-Pure ® R-931 is a rutile titanium dioxide pigmentof DuPont Titanium Technologies, Wilmington, Delaware. Imsil ® A-15 is amicrocrystalline silica of Unimin Specialty Minerals Inc., Tamms,Illinois. UCAR ® 123 is a high-solids styrene-acrylic binder of UCAREmulsion Systems, Cary, North Carolina. Texanol ® is2,2,4-trimethyl-1,3-pentanediol monoisobutyrate of Eastman ChemicalCompany, Kingsport, Tennessee. Acrosol ® RM-825 is an acrylatecopolymer-based rheology modifier of BASF AG, Ludwigshafen, Germany.

The formulations of Table 7 were tested for storage stability andviscosity as well as scrub resistance and hide of paint films on metalsurfaces.

The formulation of Example 2 was stable for several days, even betterthan that of Comparative Example 1, with less separation. Theformulation was also “creamier” (more desirable) than the comparativeformulation. This observation confirms that CarboShield® 1000 iscompatible in latex systems.

Hide, which is the ability of a coating to hide black marks, was 96.8%in the comparative example 97.2% in the example according to theinvention. This indicates that CarboShield® 1000 works better than thesurfactant Triton® X-100. Hide was measured by contrast ratio using abird bar draw down (76.2 μm=3 mil) on a standard Leneta (type 2C) cardand are expressed as a ratio of black and white L-values (LAB colorsystem).

The scrub resistance of the paint film prepared from the formulation ofExample 2 was 480 cycles to failure while that of the film prepared fromthe formulation of Comparative Example 1 was only 370 cycles to failure.This is a significant ca. 30% improvement. Scrub resistance was measuredusing standard ASTM D2486 methodology.

Gloss measurements indicated no significant difference between thecoatings prepared from both formulations.

The Stormer viscosity of the Formulation of Example 2 was significantlyhigher than that of Comparative Example 1, 83 KU vs. 73 KU. This allowsto reduce the amount of associative thickener added to the formulation.

All patents and publications cited herein are incorporated by referencein their entirety to the same extent as if each was individuallyincorporated by reference.

1-14. (canceled)
 15. An anticorrosive paint comprising (a) at least onequaternary ammonium salt containing a non-halogen anion, (b) a binder,(c) optionally, a solvent and (d) optionally, a pigment.
 16. Theanticorrosive paint of claim 15, wherein the quaternary ammonium salthas the formula

wherein R¹ is an optionally aryl-substituted C₁₋₂₀ alkyl group, and R²is an optionally aryl-substituted C₁₋₂₀ alkyl group, R³ and R⁴independently of each other are C₁₋₄ alkyl groups, X^(n−) is an anionselected from the group consisting of hydroxide, carbonate, bicarbonate,phosphates, phosphites, hypophosphite, nitrate, sulfates, borates,anions of saturated and unsaturated acyclic C₁₋₂₀ monocarboxylic acids,anions of saturated and unsaturated acyclic C₂₋₂₀ dicarboxylic acids andanions of hydroxy-substituted carboxylic acids, and n denotes theappropriate number of negative charges of said anion.
 17. Theanticorrosive paint of claim 15, wherein the binder is selected from thegroup consisting of acrylic resins, casein (milk protein), vinyl resins,latex resins, acetate resins, epoxy resins and mixtures thereof.
 18. Theanticorrosive paint of claim 15, which is a latex paint.
 19. Theanticorrosive paint of claim 15, which is an enamel spray paint.
 20. Theanticorrosive paint of claim 15, which is an e-coating paint.
 21. Theanticorrosive paint of claim 15, which is an acrylic paint.
 22. Anarticle of manufacture comprising a metal substrate painted with theanticorrosive paint of any of claim
 15. 23. A method of preparing ananticorrosive paint or coating comprising adding to the paint or coatinga quaternary ammonium salt having the formula

wherein R¹ is an optionally aryl-substituted C₁₋₂₀ alkyl group, and R²is an optionally aryl-substituted C₁₋₂₀ alkyl group, R³ and R⁴independently of each other are C₁₋₄ alkyl groups, X^(n−) is an anionselected from the group consisting of hydroxide, carbonate, bicarbonate,phosphates, phosphites, hypophosphite, nitrate, sulfates, borates,anions of saturated and unsaturated acyclic C₁₋₂₀ monocarboxylic acids,anions of saturated and unsaturated acyclic C₂₋₂₀ dicarboxylic acids andanions of hydroxy-substituted carboxylic acids, and n denotes theappropriate number of negative charges of said anion.